Ticket #3100: Embedded torrent viewer/vfs

Currently ext.d viewer for torrent is partially broken since ctorrent
is used and it broken in most distributions (http://sourceforge.net/p/dtorrent/bugs/21/).

This patch adds viewer and vfs support based on script found here: http://phdru.name/Software/mc/torrent

Signed-off-by: Slava Zanko <slavazanko@gmail.com>

misc/ext.d/misc.sh.in

@@ -45,7 +45,7 @@ do_view_action() {
         lyxcat "${MC_EXT_FILENAME}"
         ;;
     torrent)
-        ctorrent -x "${MC_EXT_FILENAME}" 2>/dev/null
+        @EXTHELPERSDIR@/../extfs.d/torrent view "${MC_EXT_FILENAME}" 2>/dev/null
         ;;
     javaclass)
         jad -p "${MC_EXT_FILENAME}" 2>/dev/null

misc/mc.ext.in

@@ -663,6 +663,7 @@ shell/i/.lyx
 
 # torrent
 shell/i/.torrent
+	Open=%cd %p/torrent://
 	View=%view{ascii} @EXTHELPERSDIR@/misc.sh view torrent
 
 ### Plain compressed files ###

src/vfs/extfs/helpers/Makefile.am

@@ -6,7 +6,7 @@ EXTFSCONFFILES = sfs.ini
 EXTFS_MISC  = README README.extfs
 
 # Scripts hat don't need adaptation to the local system
-EXTFS_CONST = bpp changesetfs gitfs+ patchsetfs rpm trpm u7z
+EXTFS_CONST = bpp changesetfs gitfs+ patchsetfs rpm trpm torrent u7z
 
 # Scripts that need adaptation to the local system - source files
 EXTFS_IN    = 			\

src/vfs/extfs/helpers/torrent

@@ -0,0 +1,302 @@
+#! /usr/bin/env python
+"""Torrent Virtual FileSystem for Midnight Commander
+
+The script requires:
+Midnight Commander 3.1+ (http://www.midnight-commander.org/),
+Python 2.4+ (http://www.python.org/).
+
+Includes: eff_bdecode.py (http://effbot.org/zone/bencode.htm).
+
+For mc 4.7+ put the script in $HOME/.mc/extfs.d.
+For older versions put it in /usr/[local/][lib|share]/mc/extfs
+and add a line "torrent" to the /usr/[local/][lib|share]/mc/extfs/extfs.ini.
+Make the script executable.
+
+Run this "cd" command in the Midnight Commander (in the "bindings" file the
+command is "%cd"): cd file#torrent, where "file" is the name of your torrent
+metafile. The VFS lists all files and directories from the torrent metafile;
+all files appear empty, of course, but the sizes are shown. Filenames are
+reencoded from the metafile's encoding/codepage to the current locale.
+
+Along with the files/directories in the torrent metafile the VFS also presents
+meta information - in the form of files in .META directory. The size and
+contents of these files are taken from the corresponding fields in the torrent
+metafile. The script doesn't check if the torrent consists of a .META file or
+directory (quite unlikely).
+
+Date/time for all files is set to midnight of the 1st January of the current
+year. The filesystem is, naturally, read-only.
+
+"""
+
+__version__ = "1.1.1"
+__author__ = "Oleg Broytman <phd@phdru.name>"
+__copyright__ = "Copyright (C) 2010-2013 PhiloSoft Design"
+__license__ = "GPL"
+
+import locale, sys, os, re, logging
+
+logger = logging.getLogger('torrent-mcextfs')
+log_err_handler = logging.StreamHandler(sys.stderr)
+logger.addHandler(log_err_handler)
+logger.setLevel(logging.INFO)
+
+if len(sys.argv) < 3:
+    logger.critical("""\
+Torrent Virtual FileSystem for Midnight Commander version %s
+Author: %s
+%s
+
+This is not a program. Put the script in /usr/[local/][lib|share]/mc/extfs.
+For more information read the source!""",
+   __version__, __author__, __copyright__
+)
+    sys.exit(1)
+
+
+locale.setlocale(locale.LC_ALL, '')
+charset = locale.getpreferredencoding()
+
+def effbtokenize(text, match=re.compile("([idel])|(\d+):|(-?\d+)").match):
+    i = 0
+    while i < len(text):
+        m = match(text, i)
+        s = m.group(m.lastindex)
+        i = m.end()
+        if m.lastindex == 2:
+            yield "s"
+            yield text[i:i+int(s)]
+            i = i + int(s)
+        else:
+            yield s
+
+def effbdecode_item(next, token):
+    if token == "i":
+        # integer: "i" value "e"
+        data = int(next())
+        if next() != "e":
+            raise ValueError
+    elif token == "s":
+        # string: "s" value (virtual tokens)
+        data = next()
+    elif token == "l" or token == "d":
+        # container: "l" (or "d") values "e"
+        data = []
+        tok = next()
+        while tok != "e":
+            data.append(effbdecode_item(next, tok))
+            tok = next()
+        if token == "d":
+            data = dict(zip(data[0::2], data[1::2]))
+    else:
+        raise ValueError
+    return data
+
+def effbdecode(text):
+    try:
+        src = effbtokenize(text)
+        data = effbdecode_item(src.next, src.next())
+        for token in src: # look for more tokens
+            raise SyntaxError("trailing junk")
+    except (AttributeError, ValueError, StopIteration):
+        raise SyntaxError("syntax error")
+    return data
+
+def mctorrent_list():
+    """List the entire VFS"""
+
+    if 'info' not in torrent:
+        torrent_error('Info absent')
+
+    info = torrent['info']
+    if 'name' not in info and 'name.utf-8' not in info:
+        torrent_error('Unknown name')
+
+    codepage = torrent.get('codepage', None)
+    encoding = torrent.get('encoding', None)
+    if not encoding and codepage:
+        encoding = str(codepage)
+
+    name = info['name']
+    name_utf8 = info.get('name.utf-8', None)
+
+    if 'files' in info:
+        files = info['files']
+        paths = []
+        for file in files:
+            if 'path' not in file and 'path.utf-8' not in file:
+                torrent_error('Unknown path')
+            if 'length' not in file:
+                torrent_error('Unknown length')
+            if 'path.utf-8' in file:
+                if name_utf8:
+                    path = '/'.join([name_utf8] + file['path.utf-8'])
+                    if charset and (charset != 'utf-8'):
+                        path = path.decode('utf-8', 'replace').encode(charset, 'replace')
+                else:
+                    _name_utf8 = name
+                    if encoding and (encoding != 'utf-8'):
+                        _name_utf8 = _name_utf8.decode(encoding, 'replace').encode('utf-8', 'replace')
+                    path = '/'.join([_name_utf8] + file['path.utf-8'])
+                    if charset and (charset != 'utf-8'):
+                        path = path.decode('utf-8', 'replace').encode(charset, 'replace')
+            else:
+                if name_utf8:
+                    path = file['path']
+                    if encoding and (encoding != 'utf-8'):
+                        path = path.decode(encoding, 'replace').encode('utf-8', 'replace')
+                    path = '/'.join([name_utf8] + path)
+                    if charset and (charset != 'utf-8'):
+                        path = path.decode('utf-8', 'replace').encode(charset, 'replace')
+                else:
+                    path = '/'.join([name] + file['path'])
+                    if charset and encoding and (charset != encoding):
+                        path = path.decode(encoding, 'replace').encode(charset, 'replace')
+            length = file['length']
+            paths.append((path, length))
+    else: # One-file torrent
+        if 'length' not in info:
+            torrent_error('Unknown length')
+        length = info['length']
+        if name_utf8:
+            if charset and (charset != 'utf-8'):
+                name = name_utf8.decode('utf-8', 'replace').encode(charset, 'replace')
+        elif charset and encoding and (charset != encoding):
+            name = name.decode(encoding, 'replace').encode(charset, 'replace')
+        paths = [(name, length)]
+
+    meta = []
+    for name in 'announce', 'announce-list', 'codepage', 'comment', \
+                'created by', 'creation date', 'encoding', \
+                'nodes', 'publisher', 'publisher-url':
+        if name == 'comment' and 'comment.utf-8' in torrent:
+            data = torrent['comment.utf-8'].decode('utf-8').encode(charset, 'replace')
+            meta.append(('.META/' + name, len(data)))
+        elif name in torrent:
+            if name == 'announce-list':
+                data = decode_announce_list(torrent[name])
+            elif name == 'codepage':
+                data = str(torrent[name])
+            elif name == 'creation date':
+                data = decode_datetime(torrent[name])
+            elif name == 'nodes':
+                data = ['%s:%s' % (host, port) for host, port in torrent[name]]
+                data = '\n'.join(data)
+            else:
+                data = torrent[name]
+            meta.append(('.META/' + name, len(data)))
+
+    if 'private' in info:
+        meta.append(('.META/private', 1))
+
+    if 'piece length' in info:
+        meta.append(('.META/piece length', len(str(info['piece length']))))
+
+    for name, size in paths + meta:
+        print "-r--r--r-- 1 user group %d Jan 1 00:00 %s" % (size, name)
+
+def mctorrent_copyout():
+    """Extract a file from the VFS"""
+
+    torrent_filename = sys.argv[3]
+    real_filename = sys.argv[4]
+    data = None
+
+    for name in 'announce', 'announce-list', 'codepage', 'comment', \
+                'created by', 'creation date', 'encoding', \
+                'nodes', 'publisher', 'publisher-url':
+        if name == 'comment' and 'comment.utf-8' in torrent:
+            data = torrent['comment.utf-8'].decode('utf-8').encode(charset, 'replace')
+            meta.append(('.META/' + name, len(data)))
+        elif torrent_filename == '.META/' + name:
+            if name in torrent:
+                if name == 'announce-list':
+                    data = decode_announce_list(torrent[name])
+                elif name == 'codepage':
+                    data = str(torrent[name])
+                elif name == 'creation date':
+                    data = decode_datetime(torrent[name])
+                elif name == 'nodes':
+                    data = ['%s:%s' % (host, port) for host, port in torrent[name]]
+                    data = '\n'.join(data)
+                else:
+                    data = str(torrent[name])
+            else:
+                torrent_error('Unknown ' + name)
+            break
+
+    if torrent_filename in ('.META/private', '.META/piece length'):
+        if 'info' not in torrent:
+            torrent_error('Info absent')
+        info = torrent['info']
+        if torrent_filename == '.META/private':
+            if 'private' not in info:
+                torrent_error('Info absent')
+        if torrent_filename == '.META/piece length':
+            if 'piece length' not in info:
+                torrent_error('Info absent')
+        data = str(info[torrent_filename[len('.META/'):]])
+
+    if not torrent_filename.startswith('.META/'):
+        data = ''
+
+    if data is None:
+        torrent_error('Unknown file name')
+    else:
+        outfile = open(real_filename, 'w')
+        outfile.write(data)
+        outfile.close()
+
+def mctorrent_copyin():
+    """Put a file to the VFS"""
+    sys.exit("Torrent VFS doesn't support adding files (read-only filesystem)")
+
+def mctorrent_rm():
+    """Remove a file from the VFS"""
+    sys.exit("Torrent VFS doesn't support removing files/directories (read-only filesystem)")
+
+mctorrent_rmdir = mctorrent_rm
+
+def mctorrent_mkdir():
+    """Create a directory in the VFS"""
+    sys.exit("Torrent VFS doesn't support creating directories (read-only filesystem)")
+
+def torrent_error(error_str):
+    logger.critical("Error parsing the torrent metafile: %s", error_str)
+    sys.exit(1)
+
+def decode_torrent():
+    try:
+        torrent_file = open(sys.argv[2], 'r')
+        data = torrent_file.read()
+        torrent_file.close()
+        return effbdecode(data)
+    except IOError, error_str:
+        torrent_error(error_str)
+
+def decode_datetime(dt):
+    from time import localtime, asctime
+    the_time = float(dt)
+    l_now = localtime(the_time)
+    return asctime(l_now)
+
+def decode_announce_list(announce):
+    return '\n'.join(l[0] for l in announce)
+
+
+command = sys.argv[1]
+procname = "mctorrent_" + command
+
+g = globals()
+if not g.has_key(procname):
+    logger.critical("Unknown command %s", command)
+    sys.exit(1)
+
+torrent = decode_torrent()
+
+try:
+    g[procname]()
+except SystemExit:
+    raise
+except:
+    logger.exception("Error during run")